Electric fencing lines are commonly employed for confining livestock, e.g. cattle, sheep and horse on grazing land and as a protection against wild animals. The electric fencing lines are fencing flexes consisting of non-conducting filaments, especially plastic filaments, and one or more conducting wires which have been incorporated into the flexes. The electric fencing lines cannot harm livestock by cutting them and are also more visible for them.
Such electric fencing lines are connected at one of their ends to a high-voltage electrical energizer. The electric fencing lines themselves may extend several hundreds of meters from the high-voltage energizer. Therefore, such electric fencing lines must have a relatively low internal electrical resistance. In addition, they must possess considerable mechanical strength to accommodate the tensile forces exerted on the fencing lines as they are strung on insulated poles. Further, such electric fencing lines must be of sufficient strength to absorb the tensile forces exerted on the lines in the event that an animal runs into the lines.
A pulsed electric current is sent along the conducting wires, about one pulse per second, from an energizer which is grounded. When an animal, e.g. a horse, touches the fence it completes the circuit between the fence and the ground and receives a short, sharp but safe shock. The shock is sufficiently memorable that the animal never forgets. The electric fencing lines may also be used to subdivide pastures temporarily to insure that they are grazed uniformly, in which case the electric fencing construction may be taken down and restrung every few days forcing animals to graze different strips of land in regular rotation.
U.S. Pat. No. 5,036,166 discloses several commercially available electric fencing lines. The fencing lines thereof comprise two different types of wires: stainless steel wires and copper wires. Stainless steel wires are rust-resistant and acid-resistant and have relatively high tensile strength; therefore they serve to take up the tensile strength. On the other hand, since stainless steel wires have a relatively low electrical conductivity, copper wires with small diameter are used to provide good electrical conductivity.
GB2321762 discloses a flexible electric fence wherein only one kind of electrically conducting wires is deployed. The electrically conducting wires are made of unalloyed steel wires and have a corrosion resistant, electrically conducting coating, e.g. cladded copper. It is further disclosed that the electrical resistance of a copper-cladded unalloyed steel wire is even from 10 to 17 times lower than that of a stainless steel wire has a same diameter.
The electrical resistance of the electric fencing lines can be adjusted or limited by incorporation of copper wires or deployment of copper-cladded wires. However, the lifetime of the electric fencing lines remains a challenge.